The invention concerns more particularly a device for actuating at least one pair of valves of an internal combustion engine disposed in a housing of the type comprising, for each valve, magnetizing means, at least one spring acting on the valve toward an equilibrium position and comprising a fixed end made integral with an adjustable stop and a movable end made integral in translation to the valve, the stop comprising meshing means adapted to cooperate with mating meshing means of a control element to enable the movement of the stop with respect to the housing, so as to adjust the tare of the spring, the housing comprising an orifice located between the adjustable stops of the two valves of a same pair and intended to receive the control element adapted to cooperate selectively with the two adjustable stops of the two adjacent valves.
Such a device is described in the document WO0065203A1. To perform the adjustment of the tare of the valve springs, the device described in this document uses a tool introduced between two adjacent valve actuators. The tool is constituted by a rod equipped at its end with a disc portion whose border has a toothed sector. The toothed sector of the tool is designed to mesh with a toothed wheel whose rotation controls the movement of a movable equipment integral with one end of a spring.
However, the adjustment of the tare of a spring according to this device is difficult. Indeed, the tool must be introduced with a certain orientation in the device, to enable the toothed sector to penetrate inside the device. The tool is then moved laterally toward the toothed wheel of the movable equipment associated to a spring. The toothed sector must then be brought blindly into a position in which it meshes with the toothed wheel. In this position which is difficult to reach, the toothed sector can be set in rotation to perform the adjustment of the tare of the spring. When the springs of two adjacent valves must be adjusted, the tool which has performed the adjustment of a first spring must then be moved laterally to mesh with the adjacent toothed wheel according to the same procedure.
The structure of such a valve control device requires thus complex adjustment operations which are hardly compatible with a large-scale industrial production. In addition, the complexity of the operations required for the adjustment of the tare for the springs is susceptible to causing adjustment errors.